Book	FZJ-2021-04321

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Molecular Layer Functionalized NeuroelectronicInterfaces: From Sub-Nanometer Molecular SurfaceFunctionalization to Improved Mechanical andElectronic Cell-Chip Coupling

Wolf, N. (Corresponding author)FZJ*

2021
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-95806-570-3

Please use a persistent id in citations: http://hdl.handle.net/2128/29597  urn:nbn:de:0001-2022011237

Abstract: The interface between electronic components and biological objects plays a crucial role for thesuccess of bioelectronic devices. Since the electronics typically include different elements suchas an insulating substrate in combination with conducting electrodes, an important issue ofbioelectronics involves tailoring and optimizing the interface for any envisioned application.In this work, we present a method of functionalizing insulating substrates (SiO2) and metallicelectrodes (Pt) simultaneously with a stable monolayer of organic molecules ((3-aminopropyl)triethoxysilane (APTES)). This monolayer is characterized by various techniqueslike atomic force microscope (AFM), ellipsometry, time-of-flight secondary ion massspectrometry (ToF-SIMS), surface plasmon resonance (SPR), and streaming potentialmeasurements. The molecule layers of APTES on both substrates, Pt and SiO2, show a highmolecule density, a coverage of ~ 50 %, a long-term stability (at least one year), a positivesurface net charge, and the characteristics of a self-assembled monolayer (SAM).In the electronical characterization of the functionalized Pt electrodes via impedancespectroscopy measurements, the static properties of the electronic double layer could beseparated from the diffusive part using a specially developed model. It could be demonstratedthat compared to cleaned Pt electrodes the double layer capacitance is increased by an APTEScoating and the charge transfer resistance is reduced, which leads to a total increase of theelectronic signal transfer of ~13 %.In the final cell culture measurements, it could be shown that an APTES coating facilitates aconversion of bio-unfriendly Pt surfaces into biocompatible surfaces which allows cell growth(neurons) on both functionalized components (SiO2 and Pt) comparable to that of referencesamples coated with poly-L-lysine. Furthermore, APTES coating leads to an improvedmechanical coupling, which increases the sealing resistance and reduces losses. These increaseswere finally confirmed by electronic measurements on neurons, which showed action potentialsignals in the mV regime compared to signals of typically 200 – 400 μV obtained for referencemeasurements on PLL coated samples. Therefore, the functionalization with APTES moleculesseems to be able to greatly improve the electronic cell-chip coupling (here by ~1 500 %).This significant increase of the electronic and mechanical cell-chip coupling might represent animportant step for the improvement of neuroelectronic sensor and actuator devices.

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Contributing Institute(s):

1. Bioelektronik (IBI-3)

Research Program(s):

1. 5241 - Molecular Information Processing in Cellular Systems (POF4-524) (POF4-524)

Appears in the scientific report 2021

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